Area Forecast Discussion
Issued by NWS Indianapolis, IN

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FXUS63 KIND 011631

Area Forecast Discussion
National Weather Service Indianapolis IN
1230 PM EDT Sat Oct 1 2016

The Near Term Section has been updated below.


Issued at 143 AM EDT Sat Oct 1 2016

A strong area of broad low pressure will push across Indiana
today and tonight. This will continue to produce sporadic showers
from time to time today and tonight across the state.

The Low is expected to push to the eastern Great Lakes on Sunday.
Thus will end the weekend on a dry note with near normal
temperatures. High pressure will then build across the region to
start the next work week with dry and seasonable weather.

Shower chances will return by Wednesday Night as a frontal system
arrives from the west.


.NEAR TERM /This afternoon and Tonight/...
Issued at 1230 PM EDT Sat Oct 1 2016

Lowered pops to likely north and small chance south per radar
trends, HRRR adjacent offices.

Previous discussion follows...
Issued at 143 AM EDT Sat Oct 1 2016

Surface analysis early this morning shows that low pressure was
found across over the Lower Wabash Valley. IR images show
plentiful cloud cover across the state...with the well defined
upper low circulation in place aloft. Radar was quieter...showing
widely scattered precipitation across the forecast area.

GFS and NAM continue to suggest that the upper low will continue
to slowly drift north across Indiana today and tonight...keeping
broad cyclonic flow in place across Central Indiana. Forecast
soundings and time height sections continue to show saturation
with the lower and middle level of the column. Soundings suggest
convective temperatures within the mid 60s...which should be
reached. Thus with relatively weak forcing...but some instability
along with the cyclonic flow in place will once again expected
the occasional showers or perhaps a thunderstorm today and
tonight. Given the heating that will be needed to produce a
thunderstorm...will try to keep the thunder mention contained to
the today period. As for temps...will stick at or below a blend
for highs given the expected clouds and rain....and trend warmer
than mavmos on lows given the expected clouds.

Furthermore on the tonight period...once heating is
lost...coverage of precip should diminish as the night goes a similar set up as early this morning remains. Also
overnight...Forecast soundings show subsidence beginning to build
aloft as the upper low pulls northeast and drying is seen within
the column as the flow becomes more northwesterly. Thus will
continue to trend pops lower as the night progresses and dry air


.SHORT TERM /Sunday through Monday Night/...

Issued at 143 AM EDT Sat Oct 1 2016

Strong ridging aloft is expected to across the area starting on
Sunday. The upper will will have mostly departed to the
northeast...however broad cyclonic flow will remain as the ridging
to west builds across the Ohio valley. Forecast soundings on
Sunday fail to show much in the way of instability...along with a
weak inversion in place within the middle levels that should
inhibit any convection. Thus will try to trend toward dry forecast
with partly cloudy skies.

Little change is seen within the forecast soundings on Sunday
night through Monday night. High pressure will continue to be
building across the area...providing subsidence. Convective
temperatures should be able to be reached...resulting on just some
sct CU. Overall...will aim for just partly cloudy skies and a
blend on temps will work well.


.LONG TERM /Tuesday through next Friday/...
Issued at 221 AM EDT Sat Oct 1 2016

Ensembles in fairly good agreement with the main upper features
during this period. Upper ridging over the Ohio Valley early next
week will gradually shift east as an upper trough lifts out of the
Rockies towards Hudson Bay by late next week.

Main feature during this period will be the passage of a weakening
cold front associated with the western trough. There are still
some timing differences with the passage of the front, with the
ensembles suggest frontal passage as early as Wednesday night, or
as late as Friday. Will keep PoPs in the forecast during those
periods for now.


.AVIATION /Discussion for the 011500Z IND TAF Update/...
Issued at 940 AM EDT Sat Oct 1 2016

Added likely pops for the next few hours across north central and
northwestern counties as a couple areas of showers were pinwheeling
around the upper low which was near Muncie. Also, left fog in
through 15z over southwestern counties per latest obs.

Previous discussion follows...
Issued at 632 AM EDT Sat Oct 1 2016

Rather widespread IFR/LIFR conditions due to low ceilings and fog
currently across the area. These conditions, so far, have not
impacted the KIND terminal, probably due to the urban heat
island. Will continue to monitor trends in the KIND vicinity
up until issuance time. Expecting these low conditions to lift
and scatter out by mid to late morning.

Convective parameters look less favorable today than yesterday as
the core of the cold pocket aloft drifts into northern Indiana.
However, short term model guidance suggests vorticity center
currently drifting west through northern Indiana will rotate into
the area from the northwest this afternoon. As a result, expecting
scattered shower/thunderstorm activity to develop by early
afternoon near this feature. CB bases around 025.

Light surface winds early this morning expected to become 180-200
degrees at 6-9 kts this afternoon.




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